Syntax, or sentence structure, plays a role in reading comprehension, but how students draw on their awareness of syntax in their reading remains unclear; the mechanism is even more ambiguous in bilingual students. In this study, we evaluated the direct and indirect contributions of syntactic awareness on first-language Chinese and second-language English reading comprehension among 227 Hong Kong Chinese-English bilingual fourth graders. We designed language-shared and language-unique tasks of syntactic awareness, assessed reading comprehension in both Chinese and English, and took other reading-related cognitive and metalinguistic measures. We found a statistically significant direct effect of syntactic awareness on reading comprehension within both first-language Chinese and second-language English, along with indirect effects via word reading. Moreover, in their reading comprehension within both English and Chinese, students drew on awareness of syntactic features that are shared between English and Chinese more than those unique to either language. Students were also generally more accurate with language-shared than language-unique items, further pointing to the possibility of transfer. Our findings clarify dual roles for syntactic awareness in reading comprehension in Chinese and English, as well as transfer of awareness of syntactic structures in the two typologically distinct languages. We discuss these results in relation to theories of both reading comprehension and transfer.